I haven’t done this myself, but the Federated Search API gives you the ability to pretty much federate any content. We use it quite extensively. 

There’s like a solution where you could automate indexing net new KB articles when they are created (and vice versa when articles are deprecated). If you can do that, then the main lift is the initial index of existing content. 

One piece of advice: the URL is the unique identifier for federated search content. So if KB article URLs change when, for example, the title changes, you’ll want to factor that into anything you automate. Updated titles would need to index the “new” URL and deprecate the “old” URL. 

@DannyPancratz  Thank you..